Most of the newer fresh water pumps don't require an accumulator tank. The purpose of the accumulator tank is to eliminate water pulsing, not to make the pump run less. The newer multi chamber pumps are smooth enough without the accumulator.
"Whipping" of the shaft is much more likely in v-drive configurations because of the longer shafts involved with that arrangement and also if the shaft is marginal in diameter. Short shafts and shafts well supported with bearings don't have that issue. Alignment is critical regardless.
I'm in the market for a used boat and can tell you sails matter to me and my decision to purchase or price a boat.
Rolly Tasker sails are inexpensive and OK quality. Small lofts buy and re-brand from them.
Looks like a long cutlass bearing which makes that rule less important. Do your cutlass bearings wear out relatively fast? Do you have a lot of vibration? If not it's probably OK but not ideal.
You could use one of these with a temp switch and buzzer: https://www.google.com/search?q=Water+Temperature+Adaptor&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjA8--jm8_ZAhWNmeAKHdi1AikQsAQI3AI&biw=1024&bih=653
Be careful of the temp switch you get since the water temp adapter isn't grounded so...